WAIS Comprehension

Comprehension is a supplemental subtest about social rules and general principles

The WAIS Comprehension subtest asks the person to explain the reasons or meaning behind widely understood social rules, conventions, and general principles. The task requires more than stating what someone should do; the person must explain why the action is needed.

In the Japanese WAIS-IV, Comprehension is a supplemental subtest in the Verbal Comprehension Index, or VCI. The standard VCI is calculated from the core subtests Similarities, Vocabulary, and Information, while Comprehension can examine verbal understanding from another angle when needed.

In the 2024 US WAIS-5, Comprehension remains a secondary subtest in the verbal-comprehension domain and contributes to the Verbal (Expanded Crystallized) Index and Verbal Reasoning Index. It is not one of the seven subtests used to calculate FSIQ.

The person must turn what they know into an explanation

Knowing a social rule does not by itself produce a complete response. The person must retrieve the knowledge relevant to the question, apply it to the situation, and organize it as a reason or general principle.

Several processes contribute to the answer:

• understanding the question accurately;
• retrieving relevant social and general knowledge;
• connecting that knowledge with the situation and considering reasons or consequences;
• moving beyond one specific example to an explanation that also applies in other situations; and
• expressing the explanation clearly in spoken language.

Comprehension does not measure sociability itself

Although Comprehension uses social subject matter, it does not measure sociability itself.

The subtest does not observe whether the person reads emotion from facial expression or tone of voice, manages the timing of a conversation, or behaves effectively in a group. A lower score therefore does not mean that the person lacks common sense or social ability. A higher score shows strength in explaining social rules and principles, not that the person is necessarily skilled at social interaction.

A study examining the relationship between Comprehension scores and real-world social functioning likewise did not support using this score as a general measure of sociability.

What higher and lower Comprehension scores can show

In the Japanese WAIS-IV, a higher scaled score indicates that, compared with people of the same age, the person could identify the central point of a social rule or general principle and explain its reason or meaning coherently.

A lower score can appear when an answer remains limited to one concrete situation, states an action without explaining why it matters, or does not organize several relevant reasons into a clear explanation. Useful points to examine include the range of relevant knowledge, understanding of the question, connection between the situation and the principle, generalization beyond one example, and spoken expression.

If Comprehension is clearly higher than Information within the person's profile, explaining a reason from acquired knowledge may be a relative strength compared with recalling general facts. If it is clearly higher than Similarities, reasoning from a social situation toward a principle may be easier than bringing two concepts together under one shared relationship. How to read WAIS results explains how to interpret these differences within the complete profile.

How Comprehension differs from Similarities and Information

Comprehension, Similarities, and Information all involve crystallized intelligence and verbal understanding. They differ in the final use made of acquired language and knowledge.